<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"> 
<title>菜鸟教程(runoob.com)</title> <!--演示如何使用百分比值来设置元素的最大宽度-->
<style>
p
{
	max-width:20%;/*设置元素的最大宽度*/
	background-color:yellow;
}
</style>
</head>
<body>

<p>This is some text. This is some text. This is some text.
This is some text. This is some text. This is some text.
This is some text. This is some text. This is some text.</p>

</body>
</html>